The capsule – which is less than a third of an inch long – disappeared somewhere along the more than 800-mile route between Newman and Perth, the department said. It contains caesium-137, a radioactive material used in gauges used in mining, one of the main industries in resource-rich Western Australia.
Despite its small size, the capsule is dangerous, the department warned. “Exposure to this substance could cause radiation burns or radiation sickness,” it said, warning people not to touch or move them if they encounter them. Anyone who sees the capsule should keep a distance of 5 meters from it and report it, the department said.
Authorities did not close National Highway 95 during the ordeal, although the emergency department’s accident map showed the entire stretch of road marked in red with a radioactive warning symbol.
Workers involved in the search used radiation detectors to try to locate the capsule, said Darryl Ray, acting chief of the emergency room. “We’re not trying to find the little pod with the naked eye,” he said. “Hopefully, the irradiator will take us there.” The equipment can detect radiation within a 65-foot radius, he said, adding that they were waiting for more specialized equipment to improve the search.
It is possible that the capsule has been missing for a few weeks. It left the mine on January 12 and is believed to have arrived on January 16, but its disappearance was discovered Wednesday when it was missing from the package it was shipped in, with the gauge inside being “apart” with screws and a bolt broken” was missing, the department said. According to the Associated Press, officials believe the capsule fell off the back of a truck.
Specialists are focusing on “strategic locations” along the route the truck has taken, Ray said, noting they were focusing on populated areas near Perth.
Cesium-137, the radioactive material in the capsule, is used, among other things, to detect the flow of liquid through pipes and to determine the thickness of materials such as sheet metal, according to the US Centers for Disease Control and Prevention.
Exposure to the material can cause an increased risk of cancer, radiation burns and acute radiation sickness, and possibly death, according to the CDC.